Mitsubishi Galant 9G. Manual — part 555

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-298

STEP 7. Check shift shock.
Q: Does shift shock occur sometimes?

YES : Go to Step 8.
NO : Go to Step 9.

STEP 8. Using scan tool MB991958, check data list item 11:
TP Sensor.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode.

• Item 11: TP Sensor.

• With the throttle valve in idle position, voltage should

measure between 300 and 700 mV.

• With the throttle valve in full-open position, voltage

should measure 4,000 mV or more.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 300 and 700 mV at

idle, and 4,000 mV or more at the full-open position?
YES : Go to Step 9.
NO : Check the TP sensor. Refer to GROUP13A <2.4L

Engine>, Diagnostic Trouble Code Procedures

P.13A-159

,

P.13A-169

, DTCs P0122, P0123: TP

Sensor System or refer to GROUP13B <3.8L
Engine>, Diagnostic Trouble Code Procedures

P.13B-162

,

P.13B-172

, DTCs P0122, P0123: TP

Sensor System. Then check the symptom.

STEP 9. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve
body for damage. Repair or replace the faulty parts. Refer to
GROUP 23B, Valve Body

P.23B-80

.

Replace the valve body assembly if the damages are thought
to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 10.

STEP 10. Replace the PCM.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Start over at Step 1.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-299

INSPECTION PROCEDURE 8: Shift Shock when Shifting from "N" to "D," "N" to "R" and Long Delay

.

COMMENT

If abnormal shock or delay of two seconds or more
occurs when the selector lever is moved from "N" to
"D" range or from "N" to "R" range while the engine is
idling, the cause is probably abnormal line pressure
or a malfunction of the oil pump or valve body.

.

TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CONDITION:)

• Abnormal line pressure

• Malfunction of the oil pump

• Malfunction of the valve body

• Malfunction of the PCM

DIAGNOSIS

STEP 1. Check the hydraulic pressure.
(1) Measure the hydraulic pressure of each element when the

transaxle is in 1st, 2nd or reverse. Check if each hydraulic
pressure is within the standard value. Refer to

P.23A-29

,

Hydraulic Pressure Test.

(2) If some elements pressures are within the standard value

and some are not, recheck the symptom.

Q: Are all hydraulic pressures within the standard value?

YES : Go to Step 3.
NO : Go to Step 2.

STEP 2. Adjust line pressure.
Adjust line pressure. Refer to

P.23A-42

, Line Pressure Adjust-

ment. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 3.

STEP 3. Check when shift shock occurs.
Q: When does the shift shock occur?

When engaging from "N" to "D" and "N" to "R" : Go to

Step 4.

When the vehicle starts moving : Go to Step 5.

STEP 4. Check the oil pump.
(1) Remove the transaxle.
(2) Check the oil pump (incorrect installation, damage and etc.)

and replace the oil pump assembly if necessary (The oil
pump cannot be disassembly).Refer to GROUP 23B,
Transaxle

P.23B-10

. Confirm that the malfunction symptom

is eliminated.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 6.

AC001865

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

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STEP 5. Disassemble and clean the valve body.
Check the installation bolts for looseness and the O-ring,
valves and valve body for damage. Repair or replace the faulty
parts. Refer to GROUP 23B, Valve Body

P.23B-80

.

Replace the valve body assembly if the damages are thought
to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 6.

STEP 6. Replace the PCM.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Start over at Step 1.

INSPECTION PROCEDURE 9: Shift Shock and Slipping

.

COMMENT

If shift shock when driving is due to upshifting or
downshifting and the transaxle speed become higher
than the engine speed, the cause is probably abnor-
mal line pressure or a malfunction of a solenoid
valve, oil pump, valve body or of a brake or clutch.

.

TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CONDITON:)

• Abnormal line pressure

• Malfunction of each solenoid valve

• Malfunction of the oil pump

• Malfunction of the valve body

• Malfunction of each brake or each clutch

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-301

STEP 1. Using scan tool MB991958, check actuator test.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the actuator test mode for

following items.

a. Item 01: Low-reverse solenoid valve
b. Item 02: Underdrive solenoid valve

c. Item 03: Second solenoid valve

d. Item 04: Overdrive solenoid valve

• An audible clicking or buzzing should be heard when

the solenoid valves are energized.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are the solenoid valves operating properly?

YES : Go to Step 2.
NO : Repair or replace the solenoid valves. Refer to

GROUP 23B, Valve Body

P.23B-80

. Then confirm

that the symptom is eliminated.

STEP 2. Check the hydraulic pressure.
(1) Measure the hydraulic pressure of each element. Check if

each hydraulic pressure is within the standard value. Refer
to

P.23A-29

, Hydraulic Pressure Test.

(2) If some elements pressure are within the standard value

and some are not, recheck the symptom.

Q: Are all hydraulic pressures within the standard value?

YES : Go to Step 6.
NO : Go to Step 3.

STEP 3. Adjust the line pressure.
Adjust the line pressure. Refer to

P.23A-42

, Line Pressure

Adjustment. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO : Go to Step 4.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827